Polymers and other groups attached to pigments and subsequent reactions

ABSTRACT

Methods of making a modified pigment by reacting a first chemical group and a second chemical group to form a pigment having attached a third chemical group. The first chemical group includes at least one nucleophile and the second chemical group includes at least one electrophile, or vice versa. Resulting modified pigments, and ink compositions containing such pigments, are also described.

[0001] This application claims priority to U.S. Provisional PatentApplication Ser. No. 60/174,995, filed on Jan. 7, 2000.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to pigments and chemical groupsattached onto pigments. More particularly, the present invention relatesto improved methods for attaching a variety of different types ofchemical groups, such as polymers, onto pigments.

[0004] 2. Description of Related Art

[0005] Methods exist for the grafting of polymers to the surface ofcarbon black which contain specific surface groups (e.g., phenols andcarboxyl groups), such as with channel blacks. However, these methodsare not easily applied to the surface grafting of polymers onto furnaceand acetylene blacks, because these carbon blacks generally lack thesespecific functional groups. The methods described herein have theadvantage that allows for the surface grafting of polymers to thesurface of carbon black, regardless of the inherent functional groups.

[0006] Pigments having polymers grafted to their surface have been foundto provide improved performance when used in an inkjet ink. Thesematerials afford printed images which are notably more waterfast,highlighter smearfast, and smudge resistant than conventional inks. Theprinted images also show improved edge acuity and intercolorbleedproperties. The dispersion stability is also greatly improved.

[0007] U.S. Pat. No. 5,851,280 discloses methods for the attachment oforganic groups onto pigments, including via a diazonium reaction whereinthe organic group is part of the diazonium salt. Through reaction with apigment, like carbon black, the organic group attaches onto the pigment.These modified pigments can be used in a variety of applications, suchas inks, inkjet inks, coatings, toners, plastics, rubbers, and the like.

[0008] There is a desire by those in the industry to further developmethods of attaching organic groups, and primarily polymers, ontopigments for the same and similar applications described above. Theseadditional methods may provide advantageous alternatives to formingmodified pigments.

SUMMARY OF THE INVENTION

[0009] A feature of the present invention is to provide improved methodsfor the attachment of chemical groups, including polymers, ontopigments.

[0010] A further feature of the present invention is to provide novelmodified pigments and compositions containing them, such as inks andcoatings.

[0011] Additional features and advantages of the present invention willbe set forth in part in the description which follows, and in part willbe apparent from the description, or may be learned by practice of thepresent invention. The objectives and other advantages of the presentinvention will be realized and obtained by means of the elements andcombinations particularly pointed out in the written description andappended claims.

[0012] To achieve these and other advantages, and in accordance with thepurpose of the present invention, as embodied and broadly describedherein, the present invention relates to a method of making a modifiedpigment by attaching at least one chemical group onto a pigment. Themethod involves reacting a pigment having attached a first chemicalgroup with a second chemical group to form a pigment having attached athird chemical group, wherein the second chemical group reacts with thefirst chemical group to form the third chemical group. The firstchemical group contains at least one nucleophile and the second chemicalgroup contains at least one electrophile, or vice versa. Preferably, inthis method, the second chemical group is a polymer or contains apolymer.

[0013] The present invention further relates to a modified pigmentcomprising a pigment having attached at least one organic group, whereinthe organic group comprises the reaction product of at least one(2-sulfatoethyl)-sulphone group and at least one nucleophilic polymer.

[0014] The present invention further relates to a modified pigmentcomprising a pigment having attached at least one organic group, whereinthe organic group comprises the reaction product of at least one benzoicacid group and at least one nucleophilic polymer.

[0015] The present invention further relates to a modified pigmentcomprising a pigment having attached at least one organic group, whereinthe organic group comprises the reaction product of at least oneelectrophile and at least one nucleophilic polymer; and an acylatingagent.

[0016] The present invention further relates to ink compositionscontaining the modified pigments described above. The modified pigmentsof the present invention also have a variety of uses in coatings,plastics, rubbers, toners, and the like.

[0017] It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory only and are intended to provide a further explanation ofthe present invention, as claimed.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0018] The present invention relates to novel and improved methods forattaching chemical groups onto pigments. The chemical groups arepreferably organic groups and more preferably include polymeric groups.

[0019] In more detail, the present invention involves a method ofattaching at least one chemical group onto at least one type of pigment.The method involves reacting a pigment having attached a first chemicalgroup and a second chemical group such that the first chemical group andsecond chemical group react with each other to form a third chemicalgroup, which is attached to the pigment. The first chemical groupcontains at least one nucleophile and the second chemical group containsat least one electrophile or vice versa; meaning the first chemicalgroup contains at least one electrophile and the second chemical groupcontains at least one nucleophile.

[0020] For purposes of the present invention, the pigment can be anytype of pigment conventionally used by those skilled in the art, such asblack pigments and other colored pigments.

[0021] Representative examples of black pigments include various carbonblacks (Pigment Black 7) such as channel blacks, furnace blacks and lampblacks, and include, for example, carbon blacks sold under the Regal®,Black Pearls®, Elftex®, Monarch®, Mogul®, and Vulcan® trademarksavailable from Cabot Corporation (such as Black Pearls® 2000, BlackPearls® 1400, Black Pearls® 1300, Black Pearls® 1100, Black Pearls®1000, Black Pearls® 900, Black Pearls® 880, Black Pearls® 800, BlackPearls® 700, Black Pearls® L, Elftex® 8, Monarch® 1400, Monarch® 1300,Monarch® 1100, Monarch® 1000, Monarch® 900, Monarch® 880, Monarch® 800,Monarch® 700, Mogul® L, Regal® 330, Regal® 400, Vulcan® P). Othersuitable carbon blacks include, but are not limited to, Printex 40,Printex 80, Printex 300, Printex L, Printex U, Printex V, Special Black4, Special Black 5, FW200, (the foregoing available from DegussaCorporation), Raven 780, Raven 890, Raven 1020, Raven 1040, Raven 1255,Raven 1500, Raven 5000, Raven 5250 (the foregoing available fromColombian Chemical Corporation) and MA100 and MA440 available fromMitsubishi Chemical Corporation. The colored pigment will typically havea wide range of BET surface areas, as measured by nitrogen adsorption.Preferably, the colored pigment has a surface area equal to or greaterthan 85 m²/g, and more preferably equal to or greater than about 100m²/g, thereby corresponding to a smaller primary/aggregate particlesize. Such surface areas have been found to provide for a more uniformdistribution and efficient level of treating agent on the surface of thepigment and a higher percent yield of the surface-modified coloredpigment after post processing techniques. If the preferred highersurface area of the colored pigment (thereby corresponding to a smallerparticle size) is not readily available, it is well recognized by thoseskilled in the art that the colored pigment may be subject toconventional size comminution or reduction techniques, such as ball orjet milling, to reduce the pigment to the desired particle size.

[0022] The pigment may also be chosen from a wide range of conventionalcolored pigments. The colored pigment can be blue, black, brown, cyan,green, white, violet, magenta, red, yellow, as well as mixtures thereof.Suitable classes of colored pigments include, for example,anthraquinones, phthalocyanine blues, phthalocyanine greens, diazos,monoazos, pyranthrones, perylenes, heterocyclic yellows, quinacridones,and (thio)indigoids. Representative examples of phthalocyanine bluesinclude copper phthalocyanine blue and derivatives thereof (Pigment Blue15). Representative examples of quinacridones include Pigment Orange 48,Pigment Orange 49, Pigment Red 122, Pigment Red 192, Pigment Red 202,Pigment Red 206, Pigment Red 207, Pigment Red 209, Pigment Violet 19 andPigment Violet 42. Representative examples of anthraquinones includePigment Red 43, Pigment Red 194 (Perinone Red), Pigment Red 216(Brominated Pyanthrone Red) and Pigment Red 226 (Pyranthrone Red).Representative examples of perylenes include Pigment Red 123(Vermillion), Pigment Red 149 (Scarlet), Pigment Red 179 (Maroon),Pigment Red 190 (Red), Pigment Violet 19, Pigment Red 189 (Yellow ShadeRed) and Pigment Red 224. Representative examples of thioindigoidsinclude Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181,Pigment Red 198, Pigment Violet 36, and Pigment Violet 38.Representative examples of heterocyclic yellows include Pigment Yellow1, Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, PigmentYellow 14, Pigment Yellow 17, Pigment Yellow 65, Pigment Yellow 73,Pigment Yellow 74, Pigment Yellow 151, Pigment Yellow 117, PigmentYellow 128 and Pigment Yellow 138. Such pigments are commerciallyavailable in either powder or press cake form from a number of sourcesincluding, BASF Corporation, Engelhard Corporation and Sun ChemicalCorporation. Examples of other suitable colored pigments are describedin the Colour Index, 3rd edition (The Society of Dyers and Colourists,1982). The color pigment can have a wide range of BET surface areas, asmeasured by nitrogen adsorption.

[0023] Other examples of pigments include Hostafinet series such asHostafine® Yellow GR (Pigment 13), Hostafine® Yellow (Pigment 83),Hostafine® Red FRLL (Pigment Red 9), Hostafine® Rubine F6B (Pigment 184), Hostafine(® Blue 2G (Pigment Blue 15:3), Hostafine® Black T (PigmentBlack 7), and Hostafine® Black TS (Pigment Black 7), available fromHoechst Celanese Corporation, Normandy Magenta RD-2400 (Paul Uhlich),Paliogen Violet 5100 (BASF), Paliogen® Violet 5890 (BASF), PermanentViolet VT2645 (Paul Uhlich), Heliogen Green L8730 (BASF), Argyle GreenXP-111 -S (Paul Uhlich), Brilliant Green Toner GR 0991 (Paul Uhlich),Heliogen® Blue L6900, L7020 (BASF), Heliogen® Blue D6840, D7080 (BASF),Sudan Blue OS (BASF), PV Fast Blue B2GO1 (American Hoechst), IrgaliteBlue BCA (Ciba-Geigy), Paliogen® Blue 6470 (BASF), Sudan III (Matheson,Coleman, Bell), Sudan II (Matheson, Coleman, Bell), Sudan IV (Matheson,Coleman, Bell), Sudan Orange G (Aldrich), Sudan Orange 220 (BASF),Paliogen® Orange 3040 (BASF), Ortho Orange OR 2673 (Paul Uhlich),Paliogen® Yellow 152, 1560 (BASF), Lithol Fast Yellow 0991K (BASF),Paliotol Yellow 1840 (BASF), Novoperm® Yellow FG 1 (Hoechst), PermanentYellow YE 0305 (Paul Uhlich), Lumogen Yellow D0790 (BASF), Suco-GelbL1250 (BASF), Suco-Yellow D1355 (BASF), Hostaperm® Pink E (AmericanHoechst), Fanal Pink D4830 (BASF), Cinquasia Magenta (DuPont), LitholScarlet D3700 (BASF), Toluidine Red (Aldrich), Scarlet for ThermoplastNSD PS PA (Ugine Kuhlmann of Canada), E.D. Toluidine Red (Aldrich),Lithol Rubine Toner (Paul Uhlich), Lithol Scarlet 4440 (BASF), Bon Red C(Dominion Color Company), Royal Brilliant Red RD-8192 (Paul Uhlich),Oracet Pink RF (Ciba-Geigy), Paliogen® Red 3871K (BASF), Paliogen® Red3340 (BASF), and Lithol Fast Scarlet L4300 (BASF).

[0024] Besides pigments, the present invention can be used to modifycarbon materials such as a carbon fiber, a graphite fiber, a graphitepowder, carbon cloth, vitreous carbon product, and an activated carbonproduct and the like.

[0025] Mixtures of different pigments and/or carbon materials can beused in the methods of the present invention.

[0026] The first chemical group can be attached to the pigment in avariety of ways using techniques know to those of ordinary skill in theart. Preferably, the first chemical group is attached to the pigment byway of a diazonium reaction, which can be accomplished following themethods and components described in U.S. Pat. Nos. 5,922,118; 5,900,029;5,895,522; 5,885,335; 5,851,280; and 5,837,045, all incorporated intheir entireties by reference herein. In this way, the first chemicalgroup is preferably part of a diazonium salt which is reacted with thepigment in order to form a pigment having attached the first chemicalgroup. The first chemical group is therefore preferably directlyattached to the pigment. It is within the bounds of the methods of thepresent invention to use a pigment having already attached the firstchemical group, and the manner in which the attachment of the firstchemical is accomplished is not critical.

[0027] The first chemical group preferably comprises an organic group,and more preferably contains at least one aromatic group, which containspreferably at least one electrophile. As stated earlier, this chemicalgroup can alternatively or in addition contain at least one nucleophilewhen the second chemical group, to be discussed in more detail below,contains at least one electrophile. A specific example of a preferredfirst chemical group is phenyl-(2-sulfatoethyl)-sulphone.

[0028] The pigment having attached the first chemical group is thenreacted with a second chemical group. Preferably, the second chemicalgroup contains at least one polymeric group and more preferably containsone or more polyamines, polyalkylene oxides, polyols, or polyacrylates,including salts and derivatives thereof. Specific preferred examples arepolyethyleneimine or poly(vinyl alcohol). As indicated earlier, thesecond chemical group contains at least one nucleophile when the firstchemical group contains at least one electrophile. Thus, preferably thesecond chemical group is a nucleophilic polymer. Alternatively, thesecond chemical group can contain at least one electrophile when thefirst chemical group contains at least one nucleophile.

[0029] The first chemical group and/or the second chemical group canhave more than one electrophile or nucleophile present. Furthermore,when the first chemical group, for instance, contains at least oneelectrophile, this first chemical group can also contain one or morenucleophiles. In other words, the first chemical group and/or secondchemical group can contain both electrophiles and nucleophiles.Furthermore, the first chemical group and/or second chemical group cancontain more than one type of nucleophile and/or electrophile. Forinstance, the first chemical group which preferably contains at leastone electrophile can contain more than one type of electrophile. Thefirst chemical group and/or second chemical group are preferably organicgroups. More preferably, the first chemical group is at least one alkylor aromatic group. Preferred electrophiles and nucleophiles which can bepart of the first or second chemical groups are set forth in Table 1below. Note that any electrophilic group can be used with any suitablenucleophilic group (and vice versa) TABLE 1 Possible Electrophiles andNucleophiles “Electrophile” groups A “Nucleophile” groups Z Carboxylicacids and esters and sulfonyl Amines, hydroxylamine, chlorideshydrazines Acid chlorides, acyl azides, sulfonyl Alcohols andalcoholates azides, and isocyanates, isothiocyanates, and blocked formsof isocyanates (for example, malonate adducts) Ketones and aldehydesThiols and thiolates Anhydrides Carboxylates, and salts of thioacids andxanthates Amides, hydroxymethyl amides, and Amides, hydrazides,melamine-formaldehyde adducts sulfonamides, and acylated sulfonamidesImides, such as N-substituted Oximes phthalimides α,β-Unsaturatedketones, aldehydes, Carbanions, such as sulphones, sulfoxides,phosphonates, malonate and etc., and precursors to these as a result ofcyanoacetate β-elimination Alkylating agents, such as alkyl halides,Imides, such as epoxides, thioepoxides, aziridines, mono phthalimide andand disubstituted halo-triazines, succinimide oxazolines, alkylsulfonates, sulfates, and phosphonates, etc. Aromatic compounds whichundergo Electron rich aromatic addition-elimination reactions, such asrings o-fluoronitrobenzene. Imines

[0030] Preferably, when the first chemical group and the second chemicalgroup are reacted, a covalent bond or other bond forms between the twogroups which results in the third chemical group which is ultimatelyattached to the pigment. Depending upon the first chemical group and thesecond chemical group used, the resulting product (which is the thirdchemical group) may contain some by-products which are not part of thethird organic group. In other words, the first chemical group and secondchemical group may react with each other wherein the resulting reactiononly produces the third chemical group (e.g., a reaction of an aminewith an epoxide) or the resulting reaction may result in the formationof the third chemical group and by-products (e.g., a reaction of aminewith an aldehyde to yield an imine wherein water is a by-product).

[0031] Thus, the resulting third chemical group preferably is anaromatic group directly attached to the pigment and at least onepolymeric group is attached onto the aromatic group via a linking groupas defined, for example, by the reaction A+Z selected from Table 1 aboveand further detailed in the examples below.

[0032] The reaction and resulting bond between the first chemical groupand the second chemical group can be formed by any type of reaction,such as S_(N) 2 displacement reactions, 1,2 or 1,4 addition reactions,condensation reactions (such as esterification and amidation), acylationreaction, ring-forming reactions, or any other number of known chemicalreactions which preferably leads to stable bonds (e.g., covalent bonds).

[0033] As previously discussed, preferably the second chemical groupcomprises at least one polymeric group. Further examples of commerciallyavailable nucleophilic polymers which can be used in the presentinvention include, but are not limited to, polyamines, (such aspolyvinylamine, polyallylamine, branched or linearpolyethyleneimine—e.g., Lubrasols™—and salts thereof, and derivatives ofpolyethyleneimine such as acylated polyetheyleneimine), dendrimers (suchas PAMAM Starburst™ dendrimers); polyalkylene glycol derivatives (suchas polyethylene glycol and polypropylene glycol derivatives andamine-substituted polyethylene and polypropylene glycols); proteins suchas hydrolyzed gelatin; polylysine; polyols (such as polyvinyl alcoholand vinyl alcohol copolymers); polyacrylates (such as amine-substitutedand alcohol-substituted polyacrylates); and the like.

[0034] The process of the present invention can be repeated one or moretimes to attach additional groups onto the third chemical group. Whenrepeating steps, the attached third chemical group behaves like theoriginal first chemical group, and thus, an additional second chemicalgroup is used to react with the third chemical group. If the originalthird chemical group contained at least one nucleophile, then whenrepeating the process, the additional second chemical group preferablycontains at least one electrophile and vice versa if the original thirdchemical group contained at least one electrophile. When repeating, thechemical groups can be the same or different from those used in theoriginal process steps.

[0035] In other words, the modified pigment containing the thirdchemical group can be further reacted and modified. Preferably, thethird chemical group is further modified by reaction with an acylatingagent, for example, with a carboxylic acid, a derivative of a carboxylicacid, or an anhydride. More preferred is the acylation of the thirdchemical group with succinic anhydride or polyacrylic acid. Thisacylation reaction is most preferred when the third chemical groupcontains polyamines, such as polyethyleneimine.

[0036] In addition, as a modification to the above-described method, adiazonium salt precursor having the first chemical group can be firstreacted with the second chemical group to form a reaction product whichis a diazonium salt precursor having the third chemical group. Thisdiazonium salt precursor having the third chemical group can then beconverted to a diazonium salt containing the third chemical group andthen attached onto the pigment by way of a diazonium reaction asdescribed above. The diazonium salt precursor is a group that istypically stable to the reaction conditions required to react the firstchemical group with the second chemical group, and can then be convertedto a diazonium salt. Examples of the precursor group include an aromaticgroup bearing a nitro group and having the first chemical group present.In converting the precursor, one or more steps can be used. Thepreferred process involves the reduction of the nitro group to anaromatic amino group which is then reacted with sodium nitrite and acid.

[0037] More than one type of reaction product can be attached to thepigment. Therefore, a variety of different third chemical groups can beon the same pigment. In other words, different types of first chemicalgroups can be attached to the pigment. Further, different types ofsecond chemical groups can be reacted with one or more types of chemicalgroups. Thus, any combination of different first chemical groups andsecond chemical groups are possible which leads to the formation ofmultiple types of third chemical groups that are present on the pigment.

[0038] In general, the pigment having attached the first chemical groupis mixed together with the second chemical group preferably in anaqueous media, such as water, to form the reaction product having thethird chemical group. Preferably, this reaction occurs at roomtemperature, however other temperatures can be used. The modifiedpigment formed can then be post-processed by diafiltration and/or ionexchange methods and/or other methods as with other modified pigments asdescribed in the patents above.

[0039] The present invention further relates to a modified pigmentcomprising a pigment having attached at least one organic group, whereinthe organic group comprises the reaction product of the first chemicalgroup and the second chemical group. Preferably, the attached groupcomprises the reaction product of at least one first chemical group(e.g., an aromatic or alkyl group) with at least one nucleophilic orelectrophilic organic group (e.g., polymer). More preferably, theorganic group attached to the modified pigment of the present inventionis the reaction product of at least one (2-sulfatoethyl)-sulphone withat least one nucleophilic polymer. Most preferred is wherein the(2-sulfatoethyl)-sulphone is phenyl-(2-sulfatoethyl sulphone) and,further, wherein this group is directly attached to the pigment.Further, the organic group attached to the modified pigment of thepresent invention is preferably the reaction product of at least onebenzoic acid group with at least one nucleophilic polymer, and mostpreferred is wherein the benzoic acid group is directly attached to thepigment. Preferably the nucleophilic polymer comprises at least onepoly(vinyl alcohol), polyethyleneimine, polyalkylene glycol, orcombinations thereof.

[0040] The modified pigments of the present invention can be used in anumber of end use applications as described in the patents mentionedabove. The various formulations and manners of introduction to form thevariety of end uses are also described in these patents. Preferably, themodified pigments are used in inks (e.g., inkjet inks) and coatings andthe like. Generally, the modified pigment is present with at least oneliquid vehicle (e.g., aqueous or non-aqueous) and can also includeconventional ingredients, such as humectants and the like.

[0041] The present invention will be further clarified by the followingexamples, which are intended to be purely exemplary of the presentinvention.

EXAMPLES Examples 1-11

[0042] For Examples 1 - 11, a two step reaction sequence was followed,as shown in Equation 1, wherein a first chemical group containing anelectrophile (A) is first attached to the pigment surface and then asecond chemical group (a polymeric or other species) containing anucleophile (Z) is added in a subsequent step. The scheme below is meantto be illustrative, but not limiting. Table 1 above provides examples ofA to Z.

[0043] Examples are given below for A=(2-sulfatoethyl)-sulphone (2SES),carboxylic acid, and acyl azide, and Z=alcohol and amine.

[0044] An exemplary description of the 2SES mechanism is shown inEquation 2.

[0045] The (2-sulfoethyl)sulphone (2SES) functionality is an alkylatingagent precursor and therefore an electrophile. Base catalyzedelimination of the 2SES group leads to a vinyl sulphone whichsubsequently reacts with amines, alcohols, and thiols. Many usefulcompounds containing nucleophiles are available commercially to carryout this sequence.

Examples A-D—Attachment of 2SES

[0046] In the following examples, the 2SES group was attached to thepigment by diazotization of aminophenyl-(2-sulfatoethyl)-sulphone(APSES), shown in Equation 3 below. Subsequent reaction of this firstchemical group with several nucleophilic polymers is therefore possible.

[0047] The following general procedure was followed for preparing thesemodified pigments. Results are shown in Table 2 below.

[0048] Into a ProcessAll Mixer was combined carbon black powder andAPSES in distilled water according to the specified amounts listed inthe table below. This mixture was heated at 50-55° C. and mixed at 300RPM for 10 minutes. To this was added 25% (by weight of ingredients)sodium nitrite (see Table 2 below for amounts) over 10-15 minutes and anadditional 50 ml of distilled water. The resultant mixture was heated at60° C. for 2 hours. The contents were removed by dilution with water toa final concentration of ˜15% (by weight) solids and then purified bycentrifugation and diafiltration. The resulting product was a fineparticle dispersion in water. Sodium determination was performed on thisdispersion directly, with an Orion ISE probe. The results are reportedon a dry carbon black basis. Sulfur analysis was performed on dry carbonblack which was Soxhlet extracted with methanol for an overnight period.TABLE 2 25% Na + UPA CB Water NaNO₂ APSES S Na + (mmol/ mV Ex CB (g) (g)(g) (g) (%) (ppm) g) (nm) A Black Pearls ® 500 920 31.4 42.61 1.51 4,536 0.2 135 700 B Black Pearls ® 500 900 52.3 71.01 2.18  7,100 0.31124 700 C Black Pearls ® 500 850 104.6 142.02 2.48  9,281 0.4 146 700 DMonarch ® 500 850 104.6 142.02 2.99 11,028 0.48  70 1100 

[0049] Examples 1-7: Reaction of APSES-treated pigments with a polyamine(A=2SES Z=Amine):

[0050] The following general procedure was followed for preparing thesemodified pigments.

[0051] A 10-15% solids dispersion of APSES-treated carbon black wasadded dropwise at room temperature, over 1 hour, with vigorous stirring,to a solution of polyethyleneimine (1-10 molar excess of polymer overelectrophile functionality) in distilled water (volume equivalent todispersion volume). The resultant mixture was then stirred for anadditional 18-48 hours. The crude product thus obtained was purified bydiafiltration using first 10 volumes of 0.1M NaOH and then 10 volumes ofdistilled water. The resulting purified products had the followingphysical and print properties. TABLE 3 Secondary Reaction of Polyamineswith APSES-Treated Carbon Black * Ex: 1 2 3 4 5 6 7 APSES D B B B B C AProduct: (see Table 1) Polyamine PEHA PEHA PEI PEI PEI PEI PEI (1800)(1200) (600) (1200) (1200) Molar ratio 10:1 10:1 6:1 5:1 5:1 5:1 5:1Work-up Acetic Acetic NaOH, NaOH, NaOH, NaOH, NaOH, acid, acid, waterwater water water water diaf'd diaf'd diaf'd diaf'd diaf'd diaf'd diaf'dpH 5.35 5.15 8.4 9.75 9.0 8.41 8.38 S (%) 3.16 n.d. 2.12 1.59 1.75 2.171.48 N (%) 1.93 n.d. 2.82 2.53 2.14 2.77 2.52 % polymer 6% n.d. 9% 8% 7%9% 8% UPA mV 68.2 168.5 151.1 161.7 184.2 145.0 192.7 (nm): UPA 100%204.4 408.8 486.1 408.8 687.5 578.1 687.5 (nm) Print OD 1.09 1.28 1.251.28 1.37 1.15 1.34 ICB Excel. Excel. Excel. Excel. Excel. Excel. Excel.WF 10-60 5-60 5 min 1-5 min 1-5 min 5-10 1-5 min min min min HighlighterGood Good Excel. Excel. Good Good Excel. Smear # BJC4400 Inkjet printerin a standard formulation; ICB = qualitative intercolor bleedperformance rating, judged primarily at the interface between adjacentlyprinted black and yellow test bars (Excel. means no visible sign ofbleed of black ink into the yellow ink); WF = waterfastness measurewhich tests how much time is required until no ink run-off is observedwhen 0.025 ml water is dripped across the print; Highlighter smear =qualitative # measure of how much black ink is smeared when a standardfluorescent highlighter marker is rubbed across the printed text (Excel.means no visible ink is removed).

[0052] Example 8: Reaction of Polyvinyl Alcohol with APSES-treatedCarbon Black (A=2SES Z=Alcohol)

[0053] To a 250 mL 3-necked round bottom flask was charged 81.25 mL of asolution of APSES-treated carbon black, Example C. To this dispersionwas added 13.2 g poly(vinyl alcohol) (MW 13,000-23,000) while beingstirred with a mechanical agitator. The mixture was heated to reflux todissolve the polymer. A solution containing 0.45 g sodium hydroxide wasadded to the refluxing dispersion over about 30 min.

[0054] After about 1 hour the heat was reduced and stirring continuedovernight. The resulting dispersion was poured into dialysis bags(Spectra/Por CE 300,000MW cutoff) and dialyzed against distilled water(10 water exchanges). The product was tested for % polymer, as volatilesdetermined by TGA. This dialyzed product after evaporation of water was21.23% polymer (volatiles) by weight.

[0055] Median particle size in this dispersion was 200 nm. The zetapotential was—17.7 mV. A drawdown made from a 5% solids dispersion hadan optical density of 1.48, was dry to the touch at 8 min., and waswaterfast within 5 minutes.

[0056] Example 9: Reaction of PEG 750 with APSES-treated Carbon Black(A=2SES, Z=Alcohol)

[0057] To a dry 250 mL 3-necked round bottomed flask was charged 0.25 gsodium hydride (60% in oil) under a nitrogen atmosphere. The oil wasremoved by rinsing the solid with heptane. To this was added 82 g ofdried poly(ethylene glycol) (750 MW, dried by concentrating fromtoluene). This mixture was heated to 50 C. and stirred for 90 min. Tothis was added 10 g of dry APSES-treated carbon black, Example C. Thisslurry was stirred at about 50° C. overnight.

[0058] The product slurry was diluted into tetrahydrofuran (THF) andprecipitated by addition of hexane (5 parts THF/3 parts hexane). Theproduct was isolated by filtration and further purified by Soxhletextraction with 5:3 THF/hexane. The resulting product did not dispersewell in water. Volatile content by TGA was 11.5% by weight. Medianparticle size of an aqueous dispersion was 687 nm and the zeta potentialwas—28.2 mV.

[0059] Example 10: Reaction of p-Aminobenzoic Acid (PABA)-treated carbonblacks with poly(vinvl alcohol) (A=Carboxylic acid, Z=Alcohol)

[0060] To 34 mL of a dispersion of Cab-O-Jet®-300 black dispersion (5 gsolids) at 50-75° C. was added 6.5 g poly(vinyl alcohol) (MW13,000-23,000) over about 10 min. The mixture was stirred to completedissolution of the polymer. To this dispersion was added 0.275 mL conc.hydrochloric acid. The suspension was then evaporated in a forced airoven at 70° C. for 2½ days.

[0061] The solid was redispersed into 38 mL warm (75-80° C.) water withstirring. The resulting dispersion was poured into dialysis bags(Spectra/Por CE 300,000 MW cutoff) and dialyzed against distilled water(6 water exchanges). The product was tested for % polymer, as volatilesdetermined by TGA. This dialyzed product after evaporation of water was19.81% polymer (volatiles) by weight. Median particle size for thisdispersion was 268 nm.

[0062] Example 11: Preparation of PEI-substituted carbon black viareaction with acyl azide-substituted carbon black (A=acyl azide,Z=amine).

[0063] A PABA-substituted carbon black dispersion (BP700,PABA-substitution equivalent to ˜0.55 mmol/g) was dried in a 100° C.oven for several hours to afford a black solid. This material was groundinto a fine powder using a mortar and pestle under dry conditions. To 10g of this resulting powder suspended in 50 g of dry DMF was added 1.4 gof diphenylphosphoryl azide, in one portion, at room temperature. Thismixture was stirred under an atmosphere of dry nitrogen for 18 hours.During this time the suspension became a DMF dispersion. A portion ofthe resultant product was precipitated by addition to distilled waterand the black solid then filtered, washed and dried in vacuo. Combustionanalysis revealed that the sample contained 1.93% nitrogen, whichcorresponded to 0.46 mmol azide per g of solid. A portion of the aboveDMF solution (10 g) was added dropwise to a solution of 4.5 g PEI(1200)in 20 ml of distilled water. After stirring for 3 hours at roomtemperature, the mixture was diafiltered (10,000 MW cut-off membrane)using 10 volumes of 0.01M NaOH followed by 10 volumes of distilledwater. The mixture was finally concentrated to ˜12% solids. Theresulting dispersion had physical properties which were very similar toExamples 4 and 6 as shown in Table 2.

Examples 12-14

[0064] The following example demonstrates the further reaction ormodification of the modified carbon products.

[0065] Example 12: The reaction of a polyamino-Carbon Black withsuccinic anhydride:

[0066] 800 g of dispersion obtained in Example 2 (acetate salt, 12.71%solids) was pH adjusted to pH 8.2 by the addition of 2 M NaOH. To thisstirred solution, at room temperature, was added 15.3 g of succinicanhydride in 2 g increments, while maintaining the pH at 8 to 8.5 bydropwise addition of 2 M NaOH. This required a total of 150.4 g of 2MNaOH. After the addition was completed the mixture was stirred for anadditional 18 hours (overnight) at pH 8.1. The resultant mixture waspurified by diafiltration (10,000 MW cutoff, Pall Filtron membrane)using first 10 volumes of 0.01M NaOH followed by 10 volumes of distilledwater in the make-up stream. The resulting dispersion had the followingproperties: 8.35% solids, pH=10.19, viscosity (Brookfield)=1.88 cP,surface tension=75.5 dynes/cm, UPA mean volume=156 nm.

[0067] Example 13: The reaction of a polvamino-Carbon Black with aPolyacid:

[0068] 500.0 g of the dispersion obtained in Example 2 (chloride salt,12.5% solids) was added dropwise, with stirring, to a solution of 187.51g Polyacrylic acid (MW=2000) in 1.9 L of de-ionized water. The resultingmixture was transferred to a pyrex dish and heated to dryness and bakedat 150° C. for 15.5 hrs. After allowing the dried sample to cool to roomtemperature, the resultant solid residue was redispersed in 0.1 M NaOHusing a Silverson high sheer mixer. While mixing, 1.0 M NaOH was addedperiodically until the pH was in the range of 11-12. This crude productwas then purified by diafiltration (50,000 MW cutoff, Pall Filtronmembrane), using 30 volumes of 0.1 M NaOH followed by 30 volumes ofde-ionized water. The product was then filtered through a 0.5μ PallFilter to afford a dispersion with the following physical properties:11.2% solids, pH 10.2, viscosity (Brookfield)=3.4 cP, surfacetension=72.3 dynes/cm, UPA mean volume diameter=158 mn. TGA analysisshowed 10-20% polymer had been attached.

[0069] Similar reactions were run with polystyrene co-acrylic acid,polystyrene co-maleic acid, and polyacrylic ester/acid polymers of MW1000-10,000.

[0070] Example 14: The Reaction of a Polvamino Carbon Black with aPolyacid followed by Ethanol

[0071] The procedure described for Example 14 was followed. However,after allowing the dried sample to cool to room temperature, theresultant solid residue was redispersed in ethanol rather than 0.1 MNaOH (as in Example 14). The material was redispersed in 95% ethanol anddiafiltered (also with 95% ethanol) to afford a dispersion of goodquality. TGA analysis showed 31% polymer attached.

[0072] Other embodiments of the present invention will be apparent tothose skilled in the art from consideration of the specification andpractice of the invention disclosed herein as well as equivalentsthereof. It is intended that the specification and examples beconsidered as exemplary only, with a true scope and spirit of thepresent invention being indicated by the following claims andequivalents thereof.

What is claimed is:
 1. A method of making a modified pigment comprisingreacting a pigment having attached a first chemical group with a secondchemical group to form said pigment having attached a third chemicalgroup, wherein the second chemical group reacts with the first chemicalgroup to form the third chemical group, and said first chemical groupcomprises at least one electrophile and said second chemical groupcomprises at least one nucleophile, or vice versa.
 2. The method ofclaim 1, wherein said pigment having attached said first chemical groupis prepared by reacting a diazonium salt having a first chemical groupwith at least one type of pigment to form said pigment having attached agroup comprising the first chemical group.
 3. The method of claim 1,wherein the first chemical group, the second chemical group, and thethird chemical group each comprises at least one organic group.
 4. Themethod of claim 3, wherein the organic group is selected from the groupconsisting: carboxylic acids or esters, acid chlorides, sulfonylchlorides, acyl azides, isocyanates, ketones, aldehydes, anhydrides,amides, imides, imines, α,β-unsaturated ketones and aldehydes, alkylhalides, epoxides,alkyl sulfonates and sulfates, amines, hydrazines,alcohols, thiols, hydrazides, oximes, carbanions, aromatic compounds,and salts and derivatives thereof.
 5. The method of claim 1, wherein thefirst chemical group comprises an alkylsulfate group, a carboxylic acidgroup, or a salt of a carboxylic acid group.
 6. The method of claim 1,wherein the first chemical group comprises a (2-sulfatoethyl)-sulphonegroup.
 7. The method of claim 6, wherein the first chemical group isphenyl-(2-sulfatoethyl)-sulphone.
 8. The method of claim 1, wherein saidsecond chemical group comprises a polymer.
 9. The method of claim 8,wherein the polymer is selected from the group consisting: a polyamine,a polyalkylene oxide, a polyol, a polyacrylate, and salts andderivatives thereof.
 10. The method of claim 9, wherein the polymer is apolyamine.
 11. The method of claim 10, wherein the polymer ispolyethyleneimine.
 12. The method of claim 1, wherein said pigment iscarbon black.
 13. The method of claim 1, wherein said pigment comprisesa blue pigment black pigment, brown pigment, cyan pigment, greenpigment, white pigment, violet pigment, magenta pigment, red pigment,yellow pigment, or mixtures thereof.
 14. The method of claim 1, furthercomprising reacting said third chemical group attached onto said pigmentwith at least one additional second chemical group, wherein theadditional second chemical group comprises at least one electrophile andthe third chemical group comprises at least one nucleophile, or viceversa.
 15. The method of claim 14, wherein the additional secondchemical group comprises a carboxylic acid group, a acid chloride group,or an anhydride group.
 16. The method of claim 14, wherein theadditional second chemical group comprises a polymer.
 17. The method ofclaim 16, wherein the polymer is selected from the group consisting: apolyamine, a polyol, a polyalkylene glycol, a polyacrylate, a protein, apolyamino acid, and salts and derivatives thereof.
 18. The method ofclaim 16, wherein the polymer is a polyacrylate or methacrylate.
 19. Themethod of claim 18, wherein the polyacrylate is polyacrylic acid. 20.The method of claim 14, wherein the additional second chemical group issuccinic anhydride.
 21. A modified pigment comprising a pigment havingattached at least one organic group, wherein said organic groupcomprises: the reaction product of at least one(2-sulfatoethyl)-sulphone group and at least one nucleophilic polymer.22. The modified pigment of claim 21, wherein the organic group isdirectly attached to the pigment.
 23. The modified pigment of claim 21,wherein the (2-sulfatoethyl)-sulphone group isphenyl-(2-sulfatoethyl)-sulphone.
 24. The modified pigment of claim 21,wherein said nucleophilic polymer is a poly(vinyl alcohol), polyalkyleneglycol, polyamine, or combinations thereof.
 25. The modified pigment ofclaim 21, wherein the nucleophilic polymer is polyethyleneimine orderivatives or salts thereof.
 26. A modified pigment comprising apigment having attached at least one organic group, wherein said organicgroup comprises: the reaction product of at least one benzoic acid groupand at least one nucleophilic polymer.
 27. The modified pigment of claim26, wherein the benzoic acid group is directly attached to the pigment.28. The modified pigment of claim 26, wherein said nucleophile polymeris a poly(vinyl alcohol), polyalkylene glycol, polyamine, orcombinations thereof.
 29. The modified pigment of claim 26, wherein thenucleophilic polymer is polyethyleneimine or derivatives or saltsthereof.
 30. A modified pigment comprising a pigment having attached atleast one organic group, wherein said organic group comprises: thereaction product of at least one electrophile and a nucleophilicpolymer; and an acylating agent.
 31. The modified pigment of claim 30,wherein the nucleophilic polymer is a poly(vinyl alcohol), apolyalkylene oxide, a polyamine, or combinations thereof.
 32. Themodified pigment of claim 30, wherein the nucleophilic polymer ispolyethyleneimine or derivatives or salts thereof.
 33. The modifiedpigment of claim 30, wherein the acylating agent is succinic anhydrideor polyacrylic acid.
 34. An ink composition comprising a liquid vehicleand a modified pigment, wherein the modified pigment comprises a pigmenthaving attached at least one organic group, wherein said organic groupcomprises: the reaction product of a pigment having attached at leastone (2-sulfatoethyl)-sulphone group and at least one nucleophilicpolymer.
 35. The ink composition of claim 34, wherein the inkcomposition is an inkjet ink composition.
 36. An ink compositioncomprising a liquid vehicle and a modified pigment, wherein the modifiedpigment comprises a pigment having attached at least one organic group,wherein said organic group comprises: the reaction product of a pigmenthaving attached at least one benzoic acid group and at least onenucleophilic polymer.
 37. The ink composition of claim 36, wherein theink composition is an inkjet ink composition.
 38. An ink compositioncomprising a liquid vehicle and a modified pigment, wherein the modifiedpigment comprises a pigment having attached at least one organic group,wherein said organic group comprises: the reaction product of a pigmenthaving attached at least one electrophile and a nucleophilic polymer;and an acylating agent.
 39. The ink composition of claim 38, wherein theink composition is an inkjet ink composition.